Epidemiologist explains CDC guidance on 15 minutes of exposure

New guidance from the CDC says that 15 minutes of exposure – regardless of whether that occurs at one time – can result in transmission of the coronavirus.

Will SpaceX’s Starlink satellites ruin stargazing?

SpaceX’s satellites will populate the night sky, affecting how we observe the stars. And this is just the beginning of private satellite mega-constellations.

Photos of 2020’s Leonid meteor shower

EarthSky Community members around the world are sharing their photos of this year’s Leonid meteor shower. Beautiful! Thanks to all who contributed.

The SLS core stage is seen atop the B-2 test stand, ready for ignition.

NASA to test its SLS megarocket in the coming weeks

The ongoing pandemic has slowed testing for NASA’s Space Launch System megarocket, but the process is resuming and has checked off a key milestone: powering up the core stage.

Arecibo radio telescope, a large dish-type telescope built into a natural depression in the landscape in Puerto Rico.

NSF says Arecibo telescope will be dismantled

Heartbreaking news. After 57 years as a world-class resource for astronomy, the iconic Arecibo telescope is to be decommissioned, or withdrawn from service, the NSF announced today. The dish-type radio telescope – built into a natural depression in the landscape in Puerto Rico – appears to be headed for a “controlled disassembly.”

A photo showing cable damage at Arecibo Observatory.

A statement on Arecibo Observatory’s engineering options

Worrisome news regarding broken cables and engineering options at Arecibo Observatory, the iconic big radio dish in Puerto Rico.

SpaceX Crew-1 docks successfully with ISS

The SpaceX Falcon 9 rocket carrying the Crew-1 spacecraft launched Sunday evening. The rocket returned to Earth for an upright landing on a drone ship in the Atlantic Ocean. The spacecraft went on to dock with the International Space Station on Monday evening, transporting 4 astronauts.

Diwali 2020 shone in this ashram, despite Covid-19

Images of Diwali 2020 from an ashram in India.

A year with 13 Friday the 13ths?

Should we ever adopt the International Fixed Calendar, we’d have 13 months in a year, with each month containing a Friday the 13th. Friggatriskaidekaphobia – aka fear of Friday the 13th – would be rampant! Or not. Read more about this calendar system here.

A man in a suit, standing under a NASA logo, and in front of a machine assembly.

Bridenstine to step down as NASA administrator

Jim Bridenstine is leaving the post of NASA chief administrator.

2020’s second Friday the 13th is this Friday

November 13, 2020, will be the second of 2020’s two Friday the 13ths. This Friday the 13th comes exactly 39 weeks – that is, the number 3 multiplied by the number 13 – before the next Friday the 13th on August 13, 2021. Whee!

Clovis made stone tools for only around 300 years

The Clovis, some of North America’s earliest inhabitants, only made stone tools during a brief 300-year period from 13,050 to 12,750 years ago, new research shows.

The International Space Station is seeing "floating" in space with Earth in its background.

The International Space Station is 20 and going strong

20 years ago, three astronauts stepped aboard the ISS. It’s since hosted residents from many countries, creating humanity’s first history of living in space.

The upper torso and hand (holding a pen) of a person thinking and writing.

What is the Common Era?

If you encounter a date in the CE (Common Era) or BCE (Before Common Era) format, don’t fret. They mean exactly the same thing as AD (anno Domini) and BC (before Christ).

NASA re-establishes contact with Voyager 2 spacecraft

On October 29, NASA re-established contact with its Voyager 2 spacecraft, after the probe was left flying solo for 7 months while repairs were made to the radio antenna in Australia used to control it.

The Starship spacecraft is seen towering over onlookers with a clear sky backdrop.

SpaceX Starship as a trash collector in Earth orbit?

SpaceX Starship’s many tasks may include launching humans into space, carrying satellites into orbit and — perhaps — removing troublesome pieces of space debris.

Pumpkins with stars and a comet.

Halloween is a cross-quarter day

The 4 cross-quarter days fall between equinoxes and solstices. Halloween is the spookiest one – derived from a sacred festival of ancient Celts and Druids – coming as days grow short and nights long in the Northern Hemisphere.

A moon just past 1st quarter.

SOFIA finds water on the moon’s sunlit surface

For the first time ever, scientists have identified water on the moon’s sunlit surface, using SOFIA, an airborne observatory. Water on the moon also appears more widespread than previously thought.

NASA Astronaut Peggy Whitson is seen floating in the ISS while Earth's ocean is covered by clouds just outside a window's view.

What astronauts think about life away from Earth

Axiom is an aerospace company making new possibilities accessible to humanity. Watch as astronauts retell their experience launching from Earth and living in space.

Covid-19 will probably become endemic. Here’s what that means

Rather than completely disappear – even when vaccines become available- it’s likely that the coronavirus SARS-CoV-2 will be added to the family of infectious diseases known as “endemic” in the human population.